Kitt Peak hosts 16 telescopes and represents the largest
concentration of astronomical instruments in the world.

U.S. Naval Observatory
Flagstaff, Arizona
1955

This observatory houses a 40-inch Ritchey-Chretien telescope that was
originally put into operation by the U.S. Naval Observatory in
Washington, DC., in 1934. Due to increasing light and air pollution in
Washington the telescope was moved to Flagstaff, Arizona in 1955. This
telescope is the last instrument built by George W. Ritchey.

Immediately after World War II, apart from the completion in 1946, of
the U.S. Army Signal Corps project to detect radar echoes from the
moon, the only important work in radio astronomy took place here.
Research started by J.P. Hagen, F.T. Haddock, and others represented a
highly significant step, leading the way in short wave length radio
astronomy, and strongly influencing the pattern of much subsequent
research. The 50 ft. parabolic reflector, completed in 1950, was the
first radio telescope built to operate at wave lengths down to 1 cm.

NEW MEXICO

Sacramento Peak Solar Observatory
Sunspot, New Mexico
1950

The Sacramento Peak Solar Observatory is found in the Lincoln
National Forest and contains a 136-foot tower telescope dedicated to
observing the sun.

OHIO

Kraus Reflector Radio Telescope
Ohio State University
1962

This radio telescope, designed by J.D. Kraus, is a long reflector
having limited steering, with the long dimension parallel to the ground.
This type of telescope was an attractive idea for the economical
construction of a large, partially steerable radio telescope.

PUERTO RICO

Arecibo (Radio) Telescope
Puerto Rico
1963

Site of the world's largest radio astronomy dish. Used for
ionospheric studies radar mapping of the moon and planets, and radio
astronomy. Arecibo has played a major role in identifying some of the
most mysterious signals received on Earth--pulsars, quasars and natural
hydrogen emissions from the galaxies.

WEST VIRGINIA

National Radio Astronomy Observatory
Greenbank, West Virginia
1955

The National Radio Astronomy Observatory came into being in 1955 as a
result of a grant from the National Science Foundation to Associated
Universities, Inc., to establish a national radio astronomy observatory
for scientific research. The first radio telescope constructed at
Greenbank was the 85-foot Tatel Telescope. One telescope at this site,
the Reber radio telescope, is being recommended for designation in this
theme because its significance predates the establishment of the
observatory. Another instrument, the 300-foot radio telescope, was under
consideration for designation when it collapsed in late 1988.